Every clinical trial has its own set of criteria for who is eligible to participate (inclusion criteria) and who is not (exclusion criteria). This is a standard, required practice when researchers are designing their clinical trials. In order to join a clinical trial, a volunteer must meet the clinical trial’s inclusion criteria. Having any of the characteristics listed in the exclusion criteria will disqualify a volunteer from participating.

The inclusion and exclusion criteria are related to a variety of participant characteristics such as age, stage of disease (as determined by cancer staging), presence of co-occurring conditions, or previous treatment history. The purpose of having inclusion criteria is to identify the appropriate population in which researchers expect that the effect of the intervention can be demonstrated. The purpose of having exclusion criteria is to prevent certain participant characteristics from interfering with the evaluation of the intervention or increasing the risk of an unfavorable outcome. These eligibility criteria vary from one clinical trial to the next, and can be found in the clinical trial’s protocol.